Need Help! Car is running lean

[PoloTeagle]

Hey guys I’m new to this so bear with me. My car is a 2016 gt and I’ve recently installed a ported 18 intake manifold with lockouts, pmas cai, jlt catch can, and 2m fabrication long tube headers. The car is tuned by Lund. After installing everything my car now runs lean. The AFR is about 27 when I first start the car and then drops down to about 22-23 when idling. The car is throwing a p2195 code. I’m lost on what went wrong. I’ve triple checked my vacuum hoses, cleaned my maf, changed my bank 1 o2 sensor, swapped my o2 sensor extensions from side to side to see if one was bad, uninstalled and reinstalled my intake and still can’t seem to find a solution. Im lost and not sure where to go from here. Any help would be appreciated. Thanks!!

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[ugstang17]

Did you tune before or after all the mods? The way you wrote this up you were tuned by Lund and THEN did modifications. So its confusing. My guess would be that you have issues with the extensions on the O2 sensors. Many as I recall buy the F150 Coyote O2 sensors and use them because of the longer pigtail that does not require using those flaky extensions. That would be your first place to start. What does vacuum on the dash read? Should be somewhere around 18" at idle. What do STFT and LTFT's look like? IS the AFR on bank one differing from bank 2? Plenty you can do to eliminate issues through the gauges and datalogging functions on the Ngauge.

 

[3star2nr]

Hey guys I’m new to this so bear with me. My car is a 2016 gt and I’ve recently installed a ported 18 intake manifold with lockouts, pmas cai, jlt catch can, and 2m fabrication long tube headers. The car is tuned by Lund. After installing everything my car now runs lean. The AFR is about 27 when I first start the car and then drops down to about 22-23 when idling. The car is throwing a p2195 code. I’m lost on what went wrong. I’ve triple checked my vacuum hoses, cleaned my maf, changed my bank 1 o2 sensor, swapped my o2 sensor extensions from side to side to see if one was bad, uninstalled and reinstalled my intake and still can’t seem to find a solution. Im lost and not sure where to go from here. Any help would be appreciated. Thanks!!

The tune is fucked up, or just not refined enough for your application.

Send Lund a message, tell them whats happening and they will revise it...They Will probably ask u to datalog...

You can also bring it to a local dyno shop and have a tuner tune it... But since u already paid lund that's what id do.

This is just the nature of mods. With a ported manifold theres literally no predicting how the car will respond so a generic "tune" wont be enough. Also tuning for power and tunning for streetability are two very different things... Cars typically go through 3 or more years of test and tunning in different conditions, altitudes, etc before they even get released... Then the manufacturer follows up on issues and makes revisions and recalls... Once u choose to mod u throw all that out the window so it's going to take more than one pass to get the car as good as stock...

But yeah call lund today they'll fix it no problem

 

[PoloTeagle]

The tune is fucked up, or just not refined enough for your application.

Send Lund a message, tell them whats happening and they will revise it...They Will probably ask u to datalog...

You can also bring it to a local dyno shop and have a tuner tune it... But since u already paid lund that's what id do.

This is just the nature of mods. With a ported manifold theres literally no predicting how the car will respond so a generic "tune" wont be enough. Also tuning for power and tunning for streetability are two very different things... Cars typically go through 3 or more years of test and tunning in different conditions, altitudes, etc before they even get released... Then the manufacturer follows up on issues and makes revisions and recalls... Once u choose to mod u throw all that out the window so it's going to take more than one pass to get the car as good as stock...

But yeah call lund today they'll fix it no problem

I already got up with Brandon at Lund and he’s been helping me. He told me that the car was running lean on bank 1 and that I need to fix it and then send him another log. I’ve already sent him one prior

 

[PoloTeagle]

Did you tune before or after all the mods? The way you wrote this up you were tuned by Lund and THEN did modifications. So its confusing. My guess would be that you have issues with the extensions on the O2 sensors. Many as I recall buy the F150 Coyote O2 sensors and use them because of the longer pigtail that does not require using those flaky extensions. That would be your first place to start. What does vacuum on the dash read? Should be somewhere around 18" at idle. What do STFT and LTFT's look like? IS the AFR on bank one differing from bank 2? Plenty you can do to eliminate issues through the gauges and datalogging functions on the Ngauge.

The car was just on a stock tube before and then once I modded the car I flashed my new tune before the first start up. Vacuum on the dash reads about 22 at idle.

 

[PoloTeagle]

Did you tune before or after all the mods? The way you wrote this up you were tuned by Lund and THEN did modifications. So its confusing. My guess would be that you have issues with the extensions on the O2 sensors. Many as I recall buy the F150 Coyote O2 sensors and use them because of the longer pigtail that does not require using those flaky extensions. That would be your first place to start. What does vacuum on the dash read? Should be somewhere around 18" at idle. What do STFT and LTFT's look like? IS the AFR on bank one differing from bank 2? Plenty you can do to eliminate issues through the gauges and datalogging functions on the Ngauge.

Also afr on bank 2 is reading 14.7-9,

 

[PoloTeagle]

Did you tune before or after all the mods? The way you wrote this up you were tuned by Lund and THEN did modifications. So its confusing. My guess would be that you have issues with the extensions on the O2 sensors. Many as I recall buy the F150 Coyote O2 sensors and use them because of the longer pigtail that does not require using those flaky extensions. That would be your first place to start. What does vacuum on the dash read? Should be somewhere around 18" at idle. What do STFT and LTFT's look like? IS the AFR on bank one differing from bank 2? Plenty you can do to eliminate issues through the gauges and datalogging functions on the Ngauge.

STFT1 is read 23 and LTFT1 is reading -5

 

[3star2nr]

Cars can't run lean on one cylinder unless the injector for that cylinder is bad.

You can try swapping injectors over with another cylinder and seeing if the problem moves...

 

[PoloTeagle]

Cars can't run lean on one cylinder unless the injector for that cylinder is bad.

You can try swapping injectors over with another cylinder and seeing if the problem moves...

Ok I’ll try that thanks

 

[3star2nr]

Edit: miss read what u typed.

Lean condition on an entire bank is usually caused by bad o2 sensor on that bank. Other stuff like a defective crank position sensor can cause similar behavior but its rare for a crank position sensor to be bad. And since this problem started after modding stands to reason that the issue is with one of the mods

My recommendation is to keep it simple, flash the ECU back to stock, take the mods off and see if the problem is still there then reinstall one by one.

I suspect it could be anything but I mean with all the time uve spent already taking it all off maybe worth it.

I suspect that intake manifold or headers flowing unequally or something but no way to really tell that without putting it on a flowbench.

Since long tubes suck ass to get off, id swap the intake and cold air first return that to stock, flash the car back to stock and see what happens.

If the problem persists its likely the headers, either the O2 sensor got damaged during install or it's placed in a part of the exhaust stream that its not reading correctly on one bank, or an issue with the design of the headers itself.

 

[PoloTeagle]

Edit: miss read what u typed.

Lean condition on an entire bank is usually caused by bad o2 sensor on that bank. Other stuff like a defective crank position sensor can cause similar behavior but its rare for a crank position sensor to be bad.

My recommendation is to keep it simple, flash the ECU back to stock, take the mods off and see if the problem is still there then reinstall one by one.

I suspect it could be anything but I mean with all the time uve spent already taking it all off maybe worth it.

I suspect that intake manifold or headers flowing unequally or something but no way to really tell that without putting it on a flowbench.

Since long tubes suck ass to get off, id swap the intake first return that to stock, flash the car back to stock and see what happens.

If the problem persists its likely the headers the O2 sensor may have gotten damaged during install or it's placed in a part of the exhaust stream that its not reading correctly on one bank

My exhaust on that side does sound like it’s leaking. I was waiting to fix this problem before I fix the exhaust leak. Could that be a possible culprit?

 

[3star2nr]

My exhaust on that side does sound like it’s leaking. I was waiting to fix this problem before I fix the exhaust leak. Could that be a possible culprit?

Hell yes! It could cause that.

If its running lean on the bank with the leak thats the prime suspect. Or lean on the other bank.

The headers are designed to suck exhaust out of your engine, and without getting too technical, they are designed in such away that to optimize exhaust flow and be balanced between all cylinders.

If one side is leaking it's possible that the other bank is scavenging better than the other side... The computer basically doesnt know how to account for that. It assumes equal flow, so its supplying equal fuel to both banks.... It may not be enough to compensate for the leak.

By default O2 sensors arent really used for fuelling calculations at cold startup and idle.

The only thing thats strange is the job of the X pipe is to balance the flow. But yeah fix the leak first and lets see what happens. As of now that's the prime suspect

 

[PoloTeagle]

Hell yes! It could cause that.

If its running lean on the bank with the leak thats the prime suspect. Or lean on the other bank.

The headers are designed to suck exhaust out of your engine, and without getting too technical, they are designed in such away that they keep the pulses close enough to pull it out.

If one side is leaking it's possible that the other bank is scavenging better than the other side... The computer basically doesnt know how to account for that. It assumes equal flow, so equal fuel to both banks.... It may not be enough to compenate for the leak.

The only thing thats strange is the job of the X pipe is to balance the flow. But yeah fix the leak first and lets see what happens. As of now that's the prime suspect

Ok I’ll get right on it. It’s on the same side I’m having problems. I just didn’t know the leak would cause that. It sounds like a pretty big leak and it’s before the x pipe as well so hopefully that’s it

 

[ugstang17]

The tune is fucked up, or just not refined enough for your application.

Send Lund a message, tell them whats happening and they will revise it...They Will probably ask u to datalog...

You can also bring it to a local dyno shop and have a tuner tune it... But since u already paid lund that's what id do.

This is just the nature of mods. With a ported manifold theres literally no predicting how the car will respond so a generic "tune" wont be enough. Also tuning for power and tunning for streetability are two very different things... Cars typically go through 3 or more years of test and tunning in different conditions, altitudes, etc before they even get released... Then the manufacturer follows up on issues and makes revisions and recalls... Once u choose to mod u throw all that out the window so it's going to take more than one pass to get the car as good as stock...

But yeah call lund today they'll fix it no problem

Yeah its always the tune...

I love how people like to refer to remote tuning as "canned" or "generic". Big difference in remote tuning like Lund, PBD, AED, or VMP and what you get on a basic SCT X4 or BDX or some canned tune from American Muscle.

 

[ugstang17]

Ok I’ll get right on it. It’s on the same side I’m having problems. I just didn’t know the leak would cause that. It sounds like a pretty big leak and it’s before the x pipe as well so hopefully that’s it

Yes. The leak causes a venturi (sp?) effect as the exhaust gas passes by the leak. As pressure changes with the exhaust waves unmetered air gets drawn into the exhaust before the sensor and the uncombusted fresh air trick the O2 sensor into thinking there is a lean state.

Always helps and saves others time and energy when you provide all the details you have the first time.

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